A PROJECT REPORT

on

“PARKING SYSTEM USING PLC SCADA”

Submitted by

XXXXXXXXXX (121xxxxx)

XXXXXXXXX (121xxxxxxx)

XXXXXXXXXX (121xxxxx)

XXXXXXXX (121XXXXXX)

Submitted to the Department of

ELECTRONICS AND COMMUNICATION ENGINEERING

in partial fulfillment of the requirement

for the degree of

BACHELOR OF TECHNOLOGY

in

ELECTRONICS AND COMMUNICATION ENGINEERING

Under the guidance of

Mr. XXXXX

GREATER NOIDA INSTITUTE OF TECHNOLOGY, GREATER NOIDA

DR. A.P.J. ABDUL KALAM TECHNICAL, LUCKNOW

MAY 2016

i

CERTIFICATE

This is to Certified that xxxx, xxxxxx, xxxxxx & xxxxxxx have carried out their project work

presented in this report entitled “PARKING SYSTEM USING PLC SCADA” for the award

of Bachelor of Technology Degree(B.Tech) from Dr. A. P. J. Abdul Kalam Technical

University, Lucknow under my supervision. The project embodies result of original work and

studies carried out by students themselves and the contents of this project do not from the basis

for the award of any other degree of the candidate or to anybody else.

Date: Project Supervisor:

Mr. xxxxxxx

(Department of ECE)

Project coordinator: Head of Department:

Mr.xxxxxxxxxxxxxx Mr. xxxxxxxx

(Department of ECE) (Department of ECE)

ii

DECLARATION

We, xxxxxx, xxxxxxx, xxxxxxxx & xxxxxxxxx students of Bachelor of Technology Degree

(B.Tech) under the Department of Electronics Communication Engineering of Dr. A. P. J.

Abdul Kalam Technical University, Lucknow, hereby declare that all the information furnished

in this report is based on our own intensive research and is genuine.

This report does not, to the best of our knowledge, contain part of our work which has been

submitted for the award of our degree either of this university or any other university without

proper citation.

Date: 16TH May, 2016

xxxxx (121xxxxxx)

xxxxx (121xxxxxx)

xxxxx (121xxxxxx)

xxxxx (121xxxxxx)

iii

ACKNOWLEDGEMENT

This project is done as a semester project known as “PARKING SYSYTEM USING PLC SCADA”. We are

really thankful to our guide Mr. xxxxxxx and whole Department of Electronics and Communication

Engineering, Greater Noida Institute of Technology, Greater Noida, for his invaluable guidance and

assistance, without which the accomplishment of the task would have never been possible. We also thank him

for giving this opportunity to explore into the real world and realize the interrelation of Electronics and

Communication without which a society can never progress. In our present project we have chosen the topic

“PARKING SYSTEM USING PLC SCADA” which aims at parking a car with the help of the plc scada. We

believe in this technology which is aimed at helping the mankind. In the end I will also like to thank Mr.

xxxxxxx who also helped us in knowing the technicalities of the project. I will also like to express my

thankfulness to my team members.

xxxxxxxxxxxxx xxxxxxxxxxxx

(121xxxxxxx) (121xxxxx)

xxxxxxxxxxxxxxx xxxxxxxxx

(121xxxxxxx) (121xxxxxx)

iv

ABSTRACT

This project work presents the study and design of PLC based Automatic Multistoried Car Parking System.

Automatic Multistoried car parking is an arrangement which is used to park a large number of vehicles in least

possible place. For making this arrangement in a real plan very high technological instruments are required.

In this project a prototype of such a model is made. This prototype model is made for accommodating Four

cars at a time. A motor controlled elevator is used to lift the cars. Controlling of the platforms and checking

the vacancies is done by PLC.

For unparking of car, Pushbuttons is interfaced with the model for selection of required platform. Automation

is done to reduce requirement of space and also to reduce human errors, which in-turn results in highest

security and greatest flexibility. Due to these advantages, this system can be used in hotels, railway stations,

airports where crowding of car is more.

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TABLE OF CONTENTS

CERTIFICATE…………………………………………………………………………………………………….……..i

DECLARATION…………………..…………………………………………………………………………….….……ii

ACKNOWLEDGEMENTS………………………………………………..…………………….…….......……..……iii

ABSTRACT……………………………………………………………….………………….………..……..…….……iv

LIST OF TABLES………………………………………………………….……………………..………………….…ix

LIST OF FIGURES…………….……………………………………..…………………..……….……..…………..x-xi

LIST OF SYMBOL………………….......................................................……………………….……..…………..xii

LIST OF ABBREVIATIONS……...…………………………………………………..………………………..……..xiii

CHAPTER 1 INTRODUCTION 1-4

1.1. Introduction to problem 1

1.2. Objective of project work 2

1.3. Organization of report 3

CHAPTER 2 REVIEW OF EXISTING SYSTEM 5

2.1. Difficulty in finding vacant space. 5

2.2. Improper Parking 5

CHAPTER 3 WORKING OF PROTOTYPE 6-17

3.1. Working of PLCs 8

3.2. Working of Scada 13

3.3. Working of DC motors 15

3.4. Working of Power supply 16

CHAPTER 4 CONSTRUCTION 18-20

4.1. Phase I 18

4.2. Present parking solutions 18

4.2.1. Integrated parking solution 18

4.2.2. Automated parking system 19

4.2.3. Multilevel car parking system 19

4.3. Material and methodology 20

4.3.1. Components 20

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4.3.1.1. DC geared motor 20

4.3.1.2. Push buttons 20

CHAPTER 5 PROGRAMMABLE LOGIC CONTROL 21-27

5.1. Basic operation 21

5.2. Hard-wired control 22

5.3. Advantages of PLCs 23

5.4. Terminology 23

5.4.1. Sensors 23

5.4.2. Actuators 23

5.5. Discrete inputs and outputs 24

5.6. Analog inputs and outputs 24

5.7. CPU 24

5.8. Memory size and types 24

5.9. Software, hardware and firmware 25

5.10. Ladder logic programming 25

5.11. PLC scan 26

CHAPTER 6 SCADA 28-39

6.1. Real time 28

6.2. What does Scada mean? 31

6.3. Architecture 31

6.3.1. Hardware architecture 31

6.3.2. Software architecture 32

6.3.3. Communications 33

6.3.4. Interfacing 33

6.3.5. Scalability 34

6.3.6. Redundancy 34

6.4. Functionality 35

6.4.1. Access Control 35

6.4.2. MMI 35

6.4.3. Trending 35

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6.4.4. Alarm Handling 36

6.4.5. Logging/Archiving 36

6.4.6. Report generation 36

6.4.7. Automation 36

6.5. Application Development 36

6.5.1. Configuration 37

6.5.2. Development Tools 37

6.5.3. Object handling 37

6.6. Evolution 37

6.7. Engineering 38

6.8. Potentials benefits of scada 38

CHAPTER 7 RELAY 40-44

7.1. Working 40

7.2. Types of relays 40

7.2.1. Electro-mechanical relay 41

7.2.2. Solid state relay 43

7.3. A relay contact life 44

CHAPTER 8 MISCELLANEOUS COMPONENTS 45-56

8.1. Push buttons 45

8.1.1. Types of push buttons 45

8.1.2. Uses 46

8.2. Free wheel 47

8.3. Wheel 51

8.3.1. Specifications 48

8.4. Conveyor belt 48

8.4.1. Working Principle 49

8.5. DC geared motor 50

8.5.1. Working principle 51

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CHAPTER 9 SWITCH MODE POWER SUPPLY 52-61

9.1. Working principle 52

9.2. Topologies of smps 52

9.2.1. DC to DC converter 53

9.2.2. AC to DC converter 54

9.2.3. Fly back converter 55

9.2.4. Forward converter 56

CHAPTER 10 CODING & SOFTWARE 57-62

10.1. WPLSOFT 57

10.2. coding 58

CHAPTER 11 RESULTS AND CONCLUTIONS 63

11.1. Result and conclusion 63

REFERENCES 64

ix

LIST OF TABLES

Table 5.1 Scanning process

Table 5.2 Scan time

x

LIST OF FIGURES

Figure 2.1 Improper parking

Figure 3.1 Power supply rack

Figure 3.2 Back panel

Figure 3.3 CPU

Figure 3.4 CPU operating cycle

Figure 3.5 I/O system

Figure 3.6 Programming a plc

Figure 3.7 Scada programming

Figure 3.8 DC motor

Figure 4.1 Integrated parking system

Figure 4.2 Automated parking system

Figure 4.3 Multi-level parking system

Figure 5.1 PLC

Figure 5.2 PLC operation

Figure 6.1 Typical hardware system

Figure 6.2 Generic software architecture

Figure 7.1 Relay

Figure 7.2 Electro-mechanical Relay

Figure 7.3 Solid state relay

Figure 8.1 Push button

Figure 8.2 Free wheel

Figure 8.3 Wheel

Figure 8.4 Conveyor belt

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Figure 8.5 DC motor

Figure 9.1 SMPS

Figure 9.2 DC to DC converter

Figure 9.3 AC to DC converter

Figure 9.4 FLY-BACK converter

Figure 9.5 Forward converter

Figure 10.1 Coding

Figure 10.2 Coding

Figure 10.3 Coding

Figure 10.4 Coding

Figure 10.5 Coding

xii

LIST OF SYMBOLS

= Equal

+ve Positive

-ve Negative

≤ Less than or equal

≥ Greater than or equal

≠ Not equal

≈ Equivalent

xiii

LIST OF ABBREVIATION

PLC Programmable logic controller

SCADA Supervisory control and data acquisition

CPU Computer processing unit

I/P Input

LAD Ladder logic

k Kilo

CU Count up

CD Count down

I/O Input/output

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CHAPTER 1 INTRODUCTION

Automatic multistoried car parking system is very essential in the modern world where number of vehicles is increasing day by day and parking spaces in public as well as private areas are not sufficient. This project deals with a similar problem and as a solution, the system is developed wherein anyone can park more number of vehicles in a smaller space. Also by such arrangement, parking will be done systematically. Unlike any other multistoried parking, this parking system is semicircular in shape due to which availability of space for parking gets increased. Since it is completely automated system human errors are negligible and hence system is more reliable. This project makes use of a „DVP 14 SS „ PLC for controlling purpose, simple DC geared motors for circular as well as vertical movements of lift, Pushbuttons are used for operation and Relay board to drive the motors. High torque motor is required for rotational movement of lift. 1.1 INTRODUCTION TO PROBLEM India is facing a new problem nowadays – lack of sufficient parking space. With families getting smaller and the total number of motor vehicles exceeding the total number of heads per family, the parking scenario is woefully falling short of the current requirements in the country. The situation is such that on any given working day approximately 40% of the roads in urban India are taken up for just parking the cars. The problem has been further exacerbated by the fact that nowadays even people from low income group are able to own cars. The number of families with cars has become much more than what the country is able to manage. As it is, the cities in India are highly congested and on top of that the parked cars claim a lot of space that could otherwise be used in a better way. Thanks to poor, and at times zero, navigability, Indian cities are regarded as some of the worst options for living. One can also add the issue of pollution to this mix and understand the enormity of the crisis. In this context it needs to be understood that the Indian cities, with the possible exception of Chandigarh, were never planned in such a way so as to

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accommodate a deluge of cars as is the situation now. The apathy of present day urban planners has only made the situation worse. 1.2 OBJECTIVE OF THE PROJECT WORK

a) The aim of this project (under an B.Tech. programme) is to design and build a prototype car park system with PLC SCADA.

b) To develop an intelligent, user friendly automated car parking system which reduces the manpower, traffic congestion and fuel consumption of the vehicle.

c) To offer safe and secure parking slots within limited area.

1.3 ORGANIZTION OF REPORT Chapters Short description 2 Review of existing

system

-Study of existing system Demand for parking in the areas of Indian cities is twice the supply. Acute shortage of parking supply is seen in commercial areas; indiscriminate parking impedes the free flow of traffic and causes accidents.

3 Working prototype

-Explanation of working model PLC is used in the control of the prototype of the automated parking system. DC motors and Push buttons are used to provide movements to transport the vehicle in the parking system. The main advantage of this system are space optimization, cost effectiveness and security.

3

Chapters Short description 4 Construction During this period detail market survey has been done to learn available

parking systems and their utility also their literatures of different types of parking systems and its difference between have been observed.

5 Programmable logic control -Study of PLC

A programmable logic controller (PLC), also referred to as programmable controller, is the name given to a type of computer commonly used in commercial and industrial control applications.

6 SCADA SCADA systems are used to monitor and control a plant or equipment in industries such as telecommunications, water and waste control, energy, oil and gas refining and transportation. it is a purely software package that is positioned on top of hardware to which it is interfaced, in general via PLCs, or other commercial hardware modules.

7 RELAY Relays are switches that open and close circuits electromechanically or electronically. They control one electrical circuit by opening and closing contacts in another circuit. When a relay contact is normally open (NO), there is an open contact when the relay is not energized. When a relay contact is Normally Closed (NC), there is a closed contact when the relay is not energized. In either case, applying electrical current to the contacts will change their state.

8 Miscellaneous components Miscellaneous components are the various components used in project

and each component have its own significance and certain operation. Various components used in project are: - -Push buttons -Free wheel -Wheel -DC motor

4

Chapters Short description 9 SMPS Electronic power supply integrated with the switching regulator for

converting the electrical power efficiently from one form to another form with desired characteristics is called as Switch-mode power supply. It is used to obtain regulated DC output voltage from unregulated AC or DC input voltage.

10 Software and coding

WPLSoft is a software for PLC (Programmable logic controller). When PLC is in operation, use WPLSoft to monitor the set value or temporarily saved value in timer (T), counter (C), and register (D) and force On/Off of output contacts. PLC is a control system using electronic operations.

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CHAPTER 2 REVIEW OF EXISTING SYSTEM

2.1 DIFFICULTY IN FINDING VACANT SPACE Quickly finding a vacant space for parking of car especially on weekend or public holidays is very difficult task. Stadium or shopping malls are crowed on holidays and weekends which results into insufficient area for car parking. 2.2 IMPROPER PARKING Improper car parking is, when a car is not parked correctly in allocated parking area. Due Improper car parking the space allocated for parking will not be used in proper manner. This may create traffic congestion.

Figure 2.1 Improper parking

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CHAPTER 3 WORKING PROTOTYPE

When car is entered in the pallet of escalator, the ground man presses the pushbutton. After receiving the signal, PLC checks the other status and select the building no and the floor no (Ground, 1st, 2nd floor) as per the programming of PLC. After detection of parking slot, PLC gives the signal to relay board. Relay board is used as a driver to drive low voltage dc motor. High torque dc motor pulls the lift in upward direction with the help of pulley. This motor brings the lift in front of designated floor. When lift reach to the parking area then the PLC checks the status of the motor driver and gives the signal to the motor system. motor system pushes the pallet in the parking area. When the car is parked inside the parking area then PLC again sends the signal to the motor driver for reverse action of motor and system to regain original position and in between the operation if you press any other key it will not affect the working of parking system unless it gets free from its previous operation. Imagine the time that automatic smart parking systems would save you. Every time you enter your office building you have to find a parking space and spend time walking in and out of the lot as well. Imagine how much time it is costing you. Even if you just spend 5 minutes a day to park that translates to you spending more than a whole day just parking every year. If you calculate the time you spend walking in and out of the parking lot, searching for space and such it will be easily more than the above amount. Through this system we can save a lot of time. Here, PLC is used in the control of the prototype of the automated parking system. DC motors and Push buttons are used to provide movements to transport the vehicle in the parking system. The main advantage of this system are space optimization, cost effectiveness and security.

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Real view of working prototype

8

Fig : Scada view of parking

3.1 WORKING OF PLCs

A programmable logic controller is a specialized computer used to control machines and processes. It therefore shares common terms with typical PCs like central processing unit, memory, software and communications. Unlike a personal computer though the PLC is designed to survive in a rugged industrial atmosphere and to be very flexible in how it interfaces with inputs and outputs to the real world. The components that make a PLC work can be divided into three core areas.

The power supply and rack The central processing unit (CPU) The input/output (I/O) section

PLCs come in many shapes and sizes. They can be so small as to fit in your shirt pocket while more involved controls systems require large PLC racks. Smaller PLCs (a.k.a. “bricks”) are typically designed with fixed I/O points. For our consideration, we’ll look at the more modular rack based systems. It’s called “modular” because the rack can accept many different types of I/O modules that simply slide into the rack and plug in.

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Figure 3.1 power supply rack

Figure 3.2 Back panel The rack is the component that holds everything together. Depending on the needs of the control system it can be ordered in different sizes to hold more modules. Like a human spine the rack has a backplane at the rear which allows the cards to communicate with the CPU. The power supply plugs into the rack as well and

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supplies a regulated DC power to other modules that plug into the rack. The most popular power supplies work with 120 VAC or 24 VDC sources. 3.1.1 CPU : The brain of the whole PLC is the CPU module. This module typically lives in the slot beside the power supply. Manufacturers offer different types of CPUs based on the complexity needed for the system. The CPU consists of a microprocessor, memory chip and other integrated circuits to control logic, monitoring and communications. The CPU has different operating modes. In programming mode, it accepts the downloaded logic from a PC. The CPU is then placed in run mode so that it can execute the program and operate the process.

Figure 3.3 CPU

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Since a PLC is a dedicated controller it will only process this one program over and over again. One cycle through the program is called a scan time and involves reading the inputs from the other modules, executing the logic based on these inputs and then updated the outputs accordingly. The scan time happens very quickly (in the range of 1/1000th of a second). The memory in the CPU stores the program while also holding the status of the I/O and providing a means to store values.

Figure 3.4 operating cycle

3.1.2 I/O SYSTEM: The I/O system provides the physical connection between the equipment and the PLC. Opening the doors on an I/O card reveals a terminal strip where the devices connect.

Figure 3.5 I/O system

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INPUTS: Input devices can consist of digital or analog devices. A digital input card handles discrete devices which give a signal that is either on or off such as a pushbutton, limit switch, sensors or selector switches. An analog input card converts a voltage or current (e.g. a signal that can be anywhere from 0 to 20mA) into a digitally equivalent number that can be understood by the CPU. Examples of analog devices are pressure transducers, flow meters and thermocouples for temperature readings. OUTPUTS: Output devices can also consist of digital or analog types. A digital output card either turns a device on or off such as lights, LEDs, small motors, and relays. An analog output card will convert a digital number sent by the CPU to it’s real world voltage or current. Typical outputs signals can range from 0-10 VDC or 4-20mA and are used to drive mass flow controllers, pressure regulators and position controls. 3.1.3 PROGRAMMING A PLC In these modern times a PC with specially dedicated software from the PLC manufacturer is used to program a PLC. The most widely used form of programming is called ladder logic. Ladder logic uses symbols, instead of words, to emulate the real world relay logic control, which is a relic from the PLC's history. These symbols are interconnected by lines to indicate the flow of current through relay like contacts and coils. Over the years the number of symbols has increased to provide a high level of functionality. The completed program looks like a ladder but in actuality it represents an electrical circuit. The left and right rails indicate the positive and ground of a power supply. The rungs represent the wiring between the different components which in the case of a PLC are all in the virtual world of the CPU. So if you can understand how basic electrical circuits work then you can understand ladder logic. In this simplest of examples, a digital input (like a button connected to the first position on the card) when it is pressed turns on an output which energizes an indicator light.

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Figure 3.6 Programming a plc The completed program is downloaded from the PC to the PLC using a special cable that’s connected to the front of the CPU. The CPU is then put into run mode so that it can start scanning the logic and controlling the outputs. 3.2 WORKING OF SCADA SCADA (Supervisory control and data acquisition) is an industrial automation control system at the core of many modern industries, including: Energy Food and beverage Manufacturing Oil and gas Power Recycling Transportation Water and waste water And many more SCADA systems are used by private companies and public-sector service providers. SCADA works well in many different types of enterprises because they can range from simple configurations to large, complex projects. Virtually anywhere you look in today's world, there is some type of SCADA system running behind the scenes, whether at your local supermarket, refinery, waste water treatment plant, or even your own home. A SCADA system performs four functions: 1. Data acquisition

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2. Networked data communication 3. Data presentation 4. Control These functions are performed by four kinds of SCADA components: 1. Sensors (either digital or analog) and control relays that directly interface with the managed system. 2. Remote telemetry units (RTUs). These are small computerized units deployed in the field at specific sites and locations. RTUs (Remote Telemetry Units) serve as local collection points for gathering reports from sensors and delivering commands to control relays. 3. SCADA master units. These are larger computer consoles that serve as the central processor for the SCADA system. Master units provide a human interface to the system and automatically regulate the managed system in response to sensor inputs. 4. The communications network that connects the SCADA master unit to the RTUs in the field.

Figure 3.7 scada programming

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3.3 WORKING OF DC MOTORS A DC motor is any of a class of electrical machines that converts direct current electrical power into mechanical power. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current flow in part of the motor. Most types produce rotary motion; a linear motor directly produces force and motion in a straight line. DC motors were the first type widely used, since they could be powered from existing direct-current lighting power distribution systems. A DC motor's speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings. Small DC motors are used in tools, toys, and appliances. The universal can operate on direct current but is a lightweight motor used for portable power tools and appliances. Larger DC motors are used in propulsion of electric vehicles, elevator and hoists, or in drives for steel rolling mills. The advent of power electronics has made replacement of DC motors with AC motors possible in many applications.

Workings of a brushed electric motor with a two-pole rotor (armature) and permanent magnet stator. "N" and "S" designate polarities on the inside axis faces of the magnets; the outside faces have opposite polarities. The + and - signs show where the DC current is applied to the commutator which supplies current to the armature coils

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3.3.1 GEAR MOTOR A gear motor is a specific type of electrical motor that is designed to produce high torque while maintaining a low horsepower, or low speed, motor output. Gear motors can be found in many different applications, and are probably used in many devices in your home. Gear motors are commonly used in devices such as can openers, garage door openers, washing machine time control knobs and even electric alarm clocks. Common commercial applications of a gear motor include hospital beds, commercial jacks, cranes and many other applications that are too many to list.

3.3.1.1 USES: Gear Motors are used in a lot of equipment including conveyor-belt drives, home appliances, handicap and platform lifts, medical and laboratory equipment, machine tools, packaging machinery and printing presses, case erectors, box taper, hot melt glue pumps, heat shrink tunnels, tape dispensers and conveyor drives.

Figure 3.8 Gear motor

3.4 WORKING OF POWER SUPPLY A power supply is an electronic device that supplies electric energy to an electrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to

17

as electric power converters. Some power supplies are discrete, stand-alone devices, whereas others are built into larger devices along with their loads. Examples of the latter include power supplies found in desktop computers and consumer electronics devices. Every power supply must obtain the energy it supplies to its load, as well as any energy it consumes while performing that task, from an energy source. Depending on its design, a power supply may obtain energy from various types of energy sources, including electrical energy transmission systems, energy storage devices such as a batteries and fuel cells, electromechanical systems such as generators and alternators, solar power converters, or another power supply. All power supplies have a power input, which receives energy from the energy source, and a power output that delivers energy to the load. In most power supplies the power input and output consist of electrical connectors or hardwired circuit connections, though some power supplies employ wireless energy transfer in lieu of galvanic connections for the power input or output. Some power supplies have other types of inputs and outputs as well, for functions such as external monitoring and control. To provide a useable low voltage the PSU needs to do a number of things: -

Reduce the Mains AC (Alternating current) voltage to a lower level. Convert this lower voltage from AC to DC (Direct current) Regulate the DC output to compensate for varying load (current demand) Provide protection against excessive input/output voltages.

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CHAPTER 4 CONSTRUCTION

4.1 PHASE I a. Market survey

During this period detail market survey has been done to learn available parking systems and their utility also their literatures of different types of parking systems and its difference between have been observed.

b. Problems in existing systems The problems regarding the existing system have been found such as, Complicated programming, High budgets, Unfeasible design, high end robots, etc. c. Conceptual Design

Taking problem statement from above and studying the fundamental engineering concepts various concepts regarding modern parking system are prepared and amongst those best concepts design has been selected for further phases.

4.2 PRESENT PARKING SOLUTIONS 4.2.1 Integrated Car Parking Solution

Customize application suitable for various types of landscapes and buildings Structures available below the ground. Ease control by soft touch on the operation panel screen. When a vehicle stops in front of the entrance, automatically door opens and trolley transfers the vehicle to parking cell. Misleading of this solution is it should be undergrounded. By this investment increases and lot much space utilization is to be made.

Figure 4.1 Integrated Car Parking Solution

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4.2.2 Automated Car Parking The driver will pull the car onto a computer- controlled pallet, turn it off, and get out. The pallet is then lowered into the abyss of parking spaces, much like a freight elevator for cars, except it can also move sideways, not just up and down. There's an array of laser sensors that let the system know if the car doesn't fit on the pallet (although it's big enough to fit a mid-sized SUV),. The system retrieves the car when the driver returns, although this might take some time and creative maneuvering. Cars are parked two deep in some spots, so a specially tailored software system has to figure out the logistics of shuffling the various vehicles around as needed to retrieve a specific car. And for those, like me, who find it difficult to turn their vehicle around after pulling out of a space, there's an underground turntable that turns the car around before it is lifted to the surface, so the car is facing out into the driveway, ready to go. Backing out of garages or parking spaces is one of the most common causes of accidents.

Figure 4.2 Automated Car Parking

4.2.3 Multi-Level Parking A multi-level car parking is essentially a building with number of floors or layers for the cars to be parked. The different levels are accessed through interior or exterior ramps. An automated car parking has mechanized lifts which transport the car to the different levels. Therefore, these car parks need less building volume and less ground space and thus save on the cost of the building. It also does away the need for employing too many personal to monitor the place. In an automated car parking, the cars are left at the entrance and are further transported inside the building by robot trolley. Similarly, they are retrieved by the trolley and placed at the exit for the owner to drive away.

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Figure 4.3 Multi- Level Parking

4.3 MATERIALS AND METHODOLOGY

4.3.1 Components

4.3.1.1 DC geared motor (24volts): It’s a mechanically commutated electric motor, powered by direct current (DC). Generally, DC geared motor runs in both directions, but in this prototype model it is fixed uni- directionally to avoid vibrations of the systems. 4.3.1.2 Push buttons: A push-button is a simple switch mechanism for controlling some aspect of a machine or a process. Buttons are typically made out of hard material, usually plastic or metal. There are totally 8 pushbuttons. 4.3.1.4 Free Wheel: A freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel.

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CHAPTER 5 PROGRAMMABLE LOGIC CONTROLLER

A programmable logic controller (PLC), also referred to as programmable controller, is the name given to a type of computer commonly used in commercial and industrial control applications. PLCs differ from office computers in the types of tasks that they perform and the hardware and software they require to perform these tasks. While the specific applications vary widely, all PLCs monitor inputs and other variable values, make decisions based on a stored program, and control outputs to automate a process or machine.

Figure 5.1 PLC 5.1 BASIC PLC OPERATION The basic elements of a PLC include input modules or points, a central processing unit (CPU), output modules or points, and a programming device. The type of input modules or points used by a PLC depends upon the types of input devices used. Some input modules or points respond to digital inputs, also called discrete inputs, which are either on or off. Other modules or inputs respond to analog

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Input

Module

Central Processing Unit

(CPU)

Programming

Device

Operator Interface

signals. These analog signals represent machine or process conditions as a range of voltage or current values. The primary function of a PLC’s input circuitry is to convert the signals provided by these various switches and sensors into logic signals that can be used by the CPU. The CPU evaluates the status of inputs, outputs, and other variables as it executes a stored program. The CPU then sends signals to update the status of outputs. Output modules convert control signals from the CPU into digital or analog values that can be used to control various output devices. The programming device is used to enter or change the PLC’s program or to monitor or change stored values. Once entered, the program and associated variables are stored in the CPU. In addition to these basic elements, a PLC system may also incorporate an operator interface device to simplify monitoring of the machine or process.

Figure 5.2 Basic operation

5.2 HARD-WIRED CONTROL Prior to PLCs, many control tasks were performed by c on t a c to r s , control relays, and other electromechanical devices. This is often referred to as hard-wired control. Circuit diagrams had to be designed, electrical components specified and installed and wiring lists created. Electricians would then wire the components necessary to perform a specific task. If an error was made, the wires had to be reconnected correctly. A change in function or system expansion required extensive component changes and rewiring.

Output Module

M OL L M460 VAC OL T2 MotorML

O1 M

C

24 StartStop2 CC

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5.3 ADVANTAGES OF PLCs PLCs not only are capable of performing the same tasks as hard-wired control, but are also capable of many more complex applications. In addition, the PLC program and electronic communication lines replace much of the interconnecting wires required by hard-wired control. Therefore, hard-wiring, though still required to connect field devices, is less intensive. This also makes correcting errors and modifying the application easier. Some of the additional advantages of PLCs are as follows:

Smaller physical size than hard-wire solutions. Easier and faster to make changes. PLCs have integrated diagnostics and override functions. Diagnostics are centrally avai lable. Applications can be immediately documented. Applications can be duplicated faster and less expensively.

5.4 TERMINOLOGY Developing an understanding of PLCs requires learning some basic terminology. This section provides an overview of commonly used PLC terms, beginning with the terms sensor and actuator. 5.4.1 SENSORS Sensors are devices that convert a physical condition into an electrical signal for use by controller, such as a PLC. Sensors are connected to the input of a PLC. A pushbutton is one example of a sensor that is often connected to a PLC input. An electrical signal indicating the condition (open or closed) of the pushbutton contacts is sent from the pushbutton to the PLC.

5.4.2 ACTUATORS Actuators are devices that convert an electrical signal from a controller, such as a PLC, into a physical condition. Actuators are connected to the PLC output. A motor starter is one example of an actuator that is often connected to a PLC output. Depending on the status of the PLC output, the motor starter either provides power to the motor or prevents power from flowing to the motor.

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5.5 DISCRETE INPUTS AND OUTPUTS Discrete inputs and outputs, also referred to as digital inputs and outputs, are either on or off. Pushbuttons, toggle switches, limit switches, proximity switches, and relay contacts are examples of devices often connected to PLC discrete inputs. Solenoids, relay and contactor coils, and indicator lamps are examples of devices often connected to PLC discrete outputs. In the on condition, a discrete input or output is represented internal to the PLC as a logic 1. In the off condition, a discrete input or output is represented as a logic 0. 5.6 ANALOG INPUTS AND OUTPUTS Analog inputs and outputs are continuous, variable signals. Typical analog signals vary from 0 to 20 milliamps, 4 to 20 milliamps, or 0 to 10 volts. In the following example, a level transmitter monitors the level of liquid in a storage tank and sends an analog signal to a PLC input. An analog output from the PLC sends an analog signal to a panel meter calibrated to show the level of liquid in the tank. Two other analog outputs, not shown here, are connected to current-to-pneumatic transducers that control air-operated flow- control valves. This allows the PLC to automatically control the flow of liquid into and out of the storage tank. 5.7 CPU The central processor unit (CPU) is a microprocessor system that contains the system memory and is the PLC’s decision- making unit. The CPU monitors inputs, outputs, and other variables and makes decisions based on instructions held in its program memory.

5.8 MEMORY TYPES AND SIZE Kilo, abbreviated k, normally refers to 1000 units. When ta lking about computer or PLC memory, however, 1k means 1024. Random Access Memory (RAM) is memory that allows data to be written to and read from any address(location). RAM is used as a temporary storage area. RAM is volatile, meaning that the data stored in RAM will be lost if power is lost. A battery backup is required to avoid losing data in the event of a power loss. Read Only Memory (ROM) is a type of memory used were it is necessary to protect data or programs from a c c i d e n t a l erasure. The data stored in ROM can

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be read, but not changed. In addition, ROM memory is nonvolatile. This means that information will not be lost as the result of a loss of electrical power. ROM is normally used to store the programs that define the capabilities of the PLC. Erasable Programmable Read Only Memory (EPROM) provides a level of security against unauthorized or unwanted changes in a program. EPROMs are designed so that data stored in them can be read, but not easily altered. Changing EPROM data requires a special effort. UVEPROMs (ultraviolet erasable programmable read only memory) can only be erased with an ultraviolet light. EEPROM (electrically erasable programmable read only memory), can only be erased electrically. 5.9 SOFTWARE, HARDWARE AND FIRMWARE Software is the name given to computer instructions, regardless of the programming language. Essentially, software includes the instructions or programs that direct hardware. Hardware is the name given to all the physical components of a system. The PLC, the programming device, and the connecting cable are examples of hardware. Firmware is user or application specific software burned into EPROM and delivered as part of the hardware. Firmware gives the PLC its basic functionality. 5.10 LADDER LOGIC PROGRAMMING The degree of complexity of a PLC program depends upon the complexity of the application, the number and type of input and output devices, and the types of instructions used. Ladder logic (LAD) is one programming language used with PLCs. Ladder logic incorporates programming functions that are graphically displayed to resemble symbols used in hard-wired control diagrams. The left vertical line of a ladder logic diagram represents the power or energized conductor. The output coil instruction represents the neutral or return path of the circuit. The right vertical line, which represents the return path on a hard-wired control line diagram, is omitted. Ladder logic diagrams are read from left-to-right and top-to-bottom. Rungs are sometimes referred to as networks. A network may have several control elements, but only one output coil. 5.10.1 WORKING PRINCIPLE

The ladder diagram was a diagram language for automation developed in the WWII period, which is the oldest and most widely adopted language in

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automation. In the initial stage, there were only A (normally open) contact, B (normally closed) contact, output coil, timer and counter…the sort of basic devices on the ladder diagram (see the power panel that is still used today). After the invention of programmable logic controllers (PLC), the devices displayable on the ladder diagram are added with differential contact, latched coil and the application commands which were not in a traditional power panel, for example the addition, subtraction, multiplication and division operations. The working principles of the traditional ladder diagram and PLC ladder diagram are basically the same. The only difference is that the symbols on the traditional ladder diagram are more similar to its original form, and PLC ladder diagram adopts the symbols that are easy to recognize and shown on computer or data sheets. In terms of the logic of the ladder diagram, there are combination logic and sequential logic.

5.11 PLC SCAN PLC utilizes a standard scan method when evaluating user program. Scanning process:

Scan input status Read the physical input status and store the data in internal memory.

Evaluate user program Evaluate the user program with data stored in internal memory. Program scanning starts from up to down and left to right until reaching the end of the program.

Refresh the outputs Write the evaluated data to the physical outputs 5.11.1 INPUT SIGNAL PLC reads the ON/OFF status of each input and stores the status into memory before evaluating the user program. Once the external input status is stored into internal memory, any change at the external inputs will not be updated until next scan cycle starts

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Scan time: The duration of the full scan cycle (read, evaluate, write) is called “scan time.” With more I/O or longer program, scan time becomes longer.

Read

scan time PLC measures its own scan time and stores the value (0.1ms) in register D1010, minimum scan time in register D1011, and maximum scan time in register D1012.

Measure scan time

Scan time can also be measured by toggling an output every scan and then measuring the pulse width on the output being toggled.

Calculate scan time

Scan time can be calculated by adding the known time required for each instruction in the user program. For scan time information of individual instruction please refer to Ch3 in this manual.

5.11.2 OUTPUT

When END command is reached the program evaluation is complete. The output memory is transferred to the external physical outputs.

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CHAPTER 6 SCADA

SCADA: Acronym for supervisory control and data acquisition, a computer system for gathering and analyzing real time data. SCADA systems are used to monitor and control a plant or equipment in industries such as telecommunications, water and waste control, energy, oil and gas refining and transportation. A SCADA system gathers information, such as where a leak on a pipeline has occurred, transfers the information back to a central site, alerting the home station that the leak has occurred, carrying out necessary analysis and control, such as determining if the leak is critical, and displaying the information in a logical and organized fashion. SCADA systems can be relatively simple, such as one that monitors environmental conditions of a small office building, or incredibly complex, such as a system that monitors all the activity in a nuclear power plant or the activity of a municipal water system. SCADA systems were first used in the 1960s. 6.1 REAL TIME Occurring immediately. The term is used to describe a number of different computer features. For example, real-time operating systems are systems that respond to input immediately. They are used for such tasks as navigation, in which the computer must react to a steady flow of new information without interruption. Most general-purpose operating systems are not real-time because they can take a few seconds, or even minutes, to react. Real time can also refer to events simulated by a computer at the same speed that they would occur in real life. In graphics animation, for example, a real-time program would display objects moving across the screen at the same speed that they would actually move.

Last modified: Friday, January 04, 2002

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A programmable machine. The two principal characteristics of a computer are:

It responds to a specific set of instructions in a well-defined manner. It can execute a pre-recorded list of instructions (a program).

Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software. All general-purpose computers require the following hardware components:

a) memory : Enables a computer to store, at least temporarily, data and programs.

b) mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.

c) input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.

d) output device : A display screen, printer, or other device that lets you see what the computer has accomplished.

e) central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.

In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another. Computers can be generally classified by size and power as follows, though there is considerable overlap:

a) personal computer : A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

b) workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

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c) minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

d) mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

e) supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.

operating system Last modified: Friday, January 04, 2002

The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop -- it makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system. Operating systems can be classified as follows:

a) multi-user : Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.

b) multiprocessing : Supports running a program on more than one CPU. c) multitasking : Allows more than one program to run concurrently. d) multithreading : Allows different parts of a single program to run

concurrently.

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e) real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux. 6.2 What does SCADA MEAN? SCADA stands for Supervisory Control and Data Acquisition. As the name indicates, it is not a full control system, but rather focuses on the supervisory level. As such, it is a purely software package that is positioned on top of hardware to which it is interfaced, in general via Programmable Logic Controllers (PLCs), or other commercial hardware modules. SCADA systems are used not only in industrial processes: e.g. steel making, power generation (conventional and nuclear) and distribution, chemistry, but also in some experimental facilities such as nuclear fusion. The size of such plants range from a few 1000 to several 10 thousand input/output (I/O) channels. However, SCADA systems evolve rapidly and are now penetrating the market of plants with a number of I/O channels of several 100 K: we know of two cases of near to 1 M I/O channels currently under development. SCADA systems used to run on DOS, VMS and UNIX; in recent years all SCADA vendors have moved to NT and some also to Linux. 6.3 ARCHITECTURE This section describes the common features of the SCADA products that have been evaluated at CERN in view of their possible application to the control systems of the LHC detectors. 6.3.1 HARDWARE ARCHITECTURE One distinguishes two basic layers in a SCADA system: the "client layer" which caters for the man machine interaction and the "data server layer" which handles most of the process data control activities. The data servers communicate with devices in the field through process controllers. Process controllers, e.g. PLCs, are connected to the data servers either directly or via networks or fieldbuses that are proprietary (e.g. Siemens H1), or non-proprietary (e.g. Profibus). Data servers are connected to each other and to client stations via an Ethernet LAN. The data servers and client stations are NT platforms but for many products the client stations may also be W95 machines. Fig.1. shows typical hardware architecture.

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Figure 6.1: Typical Hardware Architecture

6.3.2 SOFTWARE ARCHITECTURE The products are multi-tasking and are based upon a real-time database (RTDB) located in one or more servers. Servers are responsible for data acquisition and handling (e.g. polling controllers, alarm checking, calculations, logging and archiving) on a set of parameters, typically those they are connected to.

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Figure 6.2: Generic Software Architecture However, it is possible to have dedicated servers for particular tasks, e.g. historian,

data logger, alarm handler. Fig. 2 shows a SCADA architecture that is generic for the products that were evaluated. 6.3.3 COMMUNICATIONS Internal Communication Server-client and server-server communication is in general on a publish-subscribe and event-driven basis and uses a TCP/IP protocol, i.e., a client application subscribes to a parameter which is owned by a particular server application and only changes to that parameter are then communicated to the client application. Access to Devices The data servers poll the controllers at a user defined polling rate. The polling rate may be different for different parameters. The controllers pass the requested parameters to the data servers. Time stamping of the process parameters is typically performed in the controllers and this time-stamp is taken over by the data server. If the controller and communication protocol used support unsolicited data transfer, then the products will support this too. The products provide communication drivers for most of the common PLCs and widely used field-buses, e.g., Modbus. Of the three fieldbuses that are recommended at CERN, both Profibus and Worldfip are supported but CANbus often not .Some of the drivers are based on third party products (e.g., Applicom cards) and therefore have additional cost associated with them. VME on the other hand is generally not supported.

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A single data server can support multiple communications protocols: it can generally support as many such protocols as it has slots for interface cards. The effort required to develop new drivers is typically in the range of 2-6 weeks depending on the complexity and similarity with existing drivers, and a driver development toolkit is provided for this. 6.3.4 INTERFACING Application Interfaces / Openness The provision of OPC client functionality for SCADA to access devices in an open and standard manner is developing. There still seems to be a lack of devices/controllers, which provide OPC server software, but this improves rapidly as most of the producers of controllers are actively involved in the development of this standard. OPC has been evaluated by the CERN-IT-CO group. The products also provide

an Open Data Base Connectivity (ODBC) interface to the data in the archive/logs, but not to the configuration database,

an ASCII import/export facility for configuration data, a library of APIs supporting C, C++, and Visual Basic (VB) to access data in

the RTDB, logs and archive. The API often does not provide access to the product's internal features such as alarm handling, reporting, trending, etc.

The PC products provide support for the Microsoft standards such as Dynamic Data Exchange (DDE) which allows e.g. to visualise data dynamically in an EXCEL spreadsheet, Dynamic Link Library (DLL) and Object Linking and Embedding (OLE). Database The configuration data are stored in a database that is logically centralised but physically distributed and that is generally of a proprietary format. For performance reasons, the RTDB resides in the memory of the servers and is also of proprietary format. The archive and logging format is usually also proprietary for performance reasons, but some products do support logging to a Relational Data Base Management System (RDBMS) at a slower rate either directly or via an ODBC interface. 6.3.5 SCALABILITY Scalability is understood as the possibility to extend the SCADA based control system by adding more process variables, more specialised servers (e.g. for alarm handling) or more clients. The products achieve scalability by having multiple data servers connected to multiple controllers. Each data server has its own configuration database and RTDB and is responsible for the handling of a sub-set of the process variables (acquisition, alarm handling, archiving). 6.3.6 Redundancy The products often have built in software redundancy at a server level, which is normally transparent to the user. Many of the products also provide more complete redundancy solutions if required.

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6.4 FUNCTIONALITY

6.4.1 ACCESS CONTROL Users are allocated to groups, which have defined read/write access privileges to the process parameters in the system and often also to specific product functionality. 6.4.2 MMI The products support multiple screens, which can contain combinations of synoptic diagrams and text. They also support the concept of a "generic" graphical object with links to process variables. These objects can be "dragged and dropped" from a library and included into a synoptic diagram. Most of the SCADA products that were evaluated decompose the process in "atomic" parameters (e.g. a power supply current, its maximum value, its on/off status, etc.) to which a Tag-name is associated. The Tag-names used to link graphical objects to devices can be edited as required. The products include a library of standard graphical symbols, many of which would however not be applicable to the type of applications encountered in the experimental physics community. Standard windows editing facilities are provided: zooming, re-sizing, scrolling... On-line configuration and customisation of the MMI is possible for users with the appropriate privileges. Links can be created between display pages to navigate from one view to another. 6.4.3 TRENDING The products all provide trending facilities and one can summarise the common capabilities as follows:

the parameters to be trended in a specific chart can be predefined or defined on-line

a chart may contain more than 8 trended parameters or pens and an unlimited number of charts can be displayed (restricted only by the readability)

real-time and historical trending are possible, although generally not in the same chart

historical trending is possible for any archived parameter zooming and scrolling functions are provided parameter values at the cursor position can be displayed

The trending feature is either provided as a separate module or as a graphical object (ActiveX), which can then be embedded into a synoptic display. XY and other statistical analysis plots are generally not provided. 6.4.4 ALARM HANDLING Alarm handling is based on limit and status checking and performed in the data servers. More complicated expressions (using arithmetic or logical expressions) can be developed by creating derived parameters on which status or limit checking is then performed. The alarms are logically handled centrally, i.e., the information only exists in one place and all users see the same status (e.g., the acknowledgement), and

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multiple alarm priority levels (in general many more than 3 such levels) are supported. It is generally possible to group alarms and to handle these as an entity (typically filtering on group or acknowledgement of all alarms in a group). Furthermore, it is possible to suppress alarms either individually or as a complete group. The filtering of alarms seen on the alarm page or when viewing the alarm log is also possible at least on priority, time and group. However, relationships between alarms cannot generally be defined in a straightforward manner. E-mails can be generated or predefined actions automatically executed in response to alarm conditions. 6.4.5 LOGGING/ARCHIVING The terms logging and archiving are often used to describe the same facility. However, logging can be thought of as medium-term storage of data on disk, whereas archiving is long-term storage of data either on disk or on another permanent storage medium. Logging is typically performed on a cyclic basis, i.e., once a certain file size, time period or number of points is reached the data is overwritten. Logging of data can be performed at a set frequency, or only initiated if the value changes or when a specific predefined event occurs. Logged data can be transferred to an archive once the log is full. The logged data is time-stamped and can be filtered when viewed by a user. The logging of user actions is in general performed together with either a user ID or station ID. There is often also a VCR facility to play back archived data. 6.4.6 REPORT GENERATION One can produce reports using SQL type queries to the archive, RTDB or logs. Although it is sometimes possible to embed EXCEL charts in the report, a "cut and paste" capability is in general not provided. Facilities exist to be able to automatically generate, print and archive reports. 6.4.7 AUTOMATION The majority of the products allow actions to be automatically triggered by events. A scripting language provided by the SCADA products allows these actions to be defined. In general, one can load a particular display, send an Email, run a user defined application or script and write to the RTDB. The concept of recipes is supported, whereby a particular system configuration can be saved to a file and then re-loaded at a later date. Sequencing is also supported whereby, as the name indicates, it is possible to execute a more complex sequence of actions on one or more devices. Sequences may also react to external events. Some of the products do support an expert system but none has the concept of a Finite State Machine (FSM). 6.5 APPLICATION DEVELOPMENT

6.5.1 CONFIGURATION The development of the applications is typically done in two stages. First the process parameters and associated information (e.g. relating to alarm conditions) are

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defined through some sort of parameter definition template and then the graphics, including trending and alarm displays are developed, and linked where appropriate to the process parameters. The products also provide an ASCII Export/Import facility for the configuration data (parameter definitions), which enables large numbers of parameters to be configured in a more efficient manner using an external editor such as Excel and then importing the data into the configuration database. However, many of the PC tools now have a Windows Explorer type development studio. The developer then works with a number of folders, which each contains a different aspect of the configuration, including the graphics. The facilities provided by the products for configuring very large numbers of parameters are not very strong. However, this has not really been an issue so far for most of the products to-date, as large applications are typically about 50K I/O points and database population from within an ASCII editor such as Excel is still a workable option. On-line modifications to the configuration database and the graphics is generally possible with the appropriate level of privileges. 6.5.2 DEVELOPMENT TOOLS The following development tools are provided as standard:

a graphics editor, with standard drawing facilities including freehand, lines, squares circles, etc. It is possible to import pictures in many formats as well as using predefined symbols including e.g. trending charts, etc. A library of generic symbols is provided that can be linked dynamically to variables and animated as they change. It is also possible to create links between views so as to ease navigation at run-time.

a data base configuration tool (usually through parameter templates). It is in general possible to export data in ASCII files so as to be edited through an ASCII editor or Excel.

a scripting language an Application Program Interface (API) supporting C, C++, VB a Driver Development Toolkit to develop drivers for hardware that is not

supported by the SCADA product. 6.5.3 OBJECT HANDLING The products in general have the concept of graphical object classes, which support inheritance. In addition, some of the products have the concept of an object within the configuration database. In general the products do not handle objects, but rather handle individual parameters, e.g., alarms are defined for parameters, logging is performed on parameters, and control actions are performed on parameters. The support of objects is therefore fairly superficial. 6.6 EVOLUTION SCADA vendors release one major version and one to two additional minor versions once per year. These products evolve thus very rapidly so as to take advantage of new market opportunities, to meet new requirements of their customers and to take advantage of new technologies.

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As was already mentioned, most of the SCADA products that were evaluated decompose the process in "atomic" parameters to which a Tag-name is associated. This is impractical in the case of very large processes when very large sets of Tags need to be configured. As the industrial applications are increasing in size, new SCADA versions are now being designed to handle devices and even entire systems as full entities (classes) that encapsulate all their specific attributes and functionality. In addition, they will also support multi-team development. As far as new technologies are concerned, the SCADA products are now adopting:

Web technology, ActiveX, Java, etc. OPC as a means for communicating internally between the client and server

modules. It should thus be possible to connect OPC compliant third party modules to that SCADA product.

6.7 ENGINEERING Whilst one should rightly anticipate significant development and maintenance savings by adopting a SCADA product for the implementation of a control system, it does not mean a "no effort" operation. The need for proper engineering can not be sufficiently emphasised to reduce development effort and to reach a system that complies with the requirements, that is economical in development and maintenance and that is reliable and robust. Examples of engineering activities specific to the use of a SCADA system are the definition of:

a library of objects (PLC, device, subsystem) complete with standard object behaviour (script, sequences, ...), graphical interface and associated scripts for animation,

templates for different types of "panels", e.g. alarms, instructions on how to control e.g. a device ..., a mechanism to prevent conflicting controls (if not provided with the

SCADA), alarm levels, behaviour to be adopted in case of specific alarms, ...

6.8 POTENTIAL BENEFITS OF SCADA The benefits one can expect from adopting a SCADA system for the control of experimental physics facilities can be summarised as follows:

a rich functionality and extensive development facilities. The amount of effort invested in SCADA product amounts to 50 to 100 p-years!

the amount of specific development that needs to be performed by the end-user is limited, especially with suitable engineering.

reliability and robustness. These systems are used for mission critical industrial processes where reliability and performance are paramount. In addition, specific development is performed within a well-established framework that enhances reliability and robustness.

technical support and maintenance by the vendor.

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For large collaborations, as for the CERN LHC experiments, using a SCADA system for their controls ensures a common framework not only for the development of the specific applications but also for operating the detectors. Operators experience the same "look and feel" whatever part of the experiment they control. However, this aspect also depends to a significant extent on proper engineering.

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CHAPTER 7 RELAY

A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current. The heart of a relay is an electromagnet (a coil of wire that becomes a temporary magnet when electricity flows through it). You can think of a relay as a kind of electric lever: switch it on with a tiny current and it switches on ("leverages") another appliance using a much bigger current. Why is that useful? As the name suggests, many sensors are incredibly sensitive pieces of electronic equipment and produce only small electric currents. But often we need them to drive bigger pieces of apparatus that use bigger currents. Relays bridge the gap, making it possible for small currents to activate larger ones. That means relays can work either as switches (turning things on and off) or as amplifiers (converting small currents into larger ones).

Figure 7.1 Relay

7.1 WORKING Relays are switches that open and close circuits electromechanically or electronically. Relays control one electrical circuit by opening and closing contacts in another circuit. As relay diagrams show, when a relay contact is normally open (NO), there is an open contact when the relay is not energized. When a relay contact is Normally Closed (NC), there is a closed contact when the relay is not energized. In either case, applying electrical current to the contacts will change their state. Relays are generally used to switch smaller currents in a control circuit and do not usually control power consuming devices except for small motors and Solenoids that draw low amps. Nonetheless, relays can "control" larger voltages and amperes by having an amplifying effect because a small voltage applied to a relays coil can result in a large voltage being switched by the contacts. Protective relays can prevent equipment damage by detecting electrical abnormalities, including overcurrent, undercurrent, overloads and reverse currents. In addition,

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relays are also widely used to switch starting coils, heating elements, pilot lights and audible alarms. 7.2 TYPES OF RELAYS There are two basic classifications of relays: Electromechanical and Solid State. Electromechanical relays have moving parts, whereas solid state relays have no moving parts. Advantages of Electromechanical relays include lower cost, no heat sink is required, multiple poles are available, and they can switch AC or DC with equal ease. 7.2.1 ELECTROMECHANICAL RELAYS Basic parts and functions of electromechanical relays include: Frame: Heavy-duty frame that contains and supports the parts of the relay. Coil: Wire is wound around a metal core. The coil of wire causes an electromagnetic field. Armature: A relays moving part. The armature opens and closes the contacts. An attached spring returns the armature to its original position. Contacts: The conducting part of the switch that makes (closes) or breaks (opens) a circuit.

Figure7.2 Electromechanical relay Relays involve two circuits: the energizing circuit and the contact circuit. The coil is

on the energizing side; and the relays contacts are on the contact side. When a relays coil is energized, current flow through the coil creates a magnetic field. Whether in a DC unit where the polarity is fixed, or in an AC unit where the polarity changes 120

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times per second, the basic function remains the same: the magnetic coil attracts a ferrous plate, which is part of the armature. One end of the armature is attached to the metal frame, which is formed so that the armature can pivot, while the other end opens and closes the contacts. Contacts come in a number of different configurations, depending on the number of Breaks, poles and Throws that make up the relay. For instance, relays might be described as Single-Pole, Single-Throw (SPST), or Double-Pole, Single-Throw (DPST). These terms will give an instant indication of the design and function of different types of relays. Break -This is the number of separate places or contacts that a switch uses to open or close a single electrical circuit. All contacts are either single break or double break. A single break (SB) contact breaks an electrical circuit in one place, while a double break (DB) contact breaks it in two places. Single break contacts are normally used when switching lower power devices such as indicating lights. Double break contacts are used when switching high-power devices such as solenoids. Pole -This is the number of completely isolated circuits that relays can pass through a switch. A single-pole contact (SP) can carry current through only one circuit at a time. A double-pole contact (DP) can carry current through two isolated circuits simultaneously. The maximum number of poles is 12, depending upon a relays design. Throw -This is the number of closed contact positions per pole that are available on a switch. A switch with a single throw contact can control only one circuit, while a double-throw contact can control two. 7.2.1.1 TYPE OF RELAYS General Purpose Relays are electromechanical switches, usually operated by a magnetic coil. General purpose relays operate with AC or DC current, at common voltages such as 12V, 24V, 48V, 120V and 230V, and they can control currents ranging from 2A-30A. These relays are economical, easy to replace and allow a wide range of switch configuration. Machine Control Relays are also operated by a magnetic coil. They are heavy-duty relays used to control starters and other industrial components. Although they are more expensive than general purpose relays, they are generally more durable. The biggest advantage of machine control relays over general purpose relays is the expandable functionality of Machine Control Relays by the adding of accessories. A wide selection of accessories is available for machine control relays, including additional poles, convertible contacts, transient suppression of electrical noise, latching control and timing attachments. Reed Relays are a small, compact, fast operating switch design with one contact, which is NO. Reed Relays are hermetically sealed in a glass envelope, which makes the contacts unaffected by contaminants, fumes or humidity, allows reliable switching, and gives contacts a higher life expectancy. The ends of the contact, which are often plated with gold or another low resistance material to increase conductivity, are drawn together and closed by a magnet. Reed relays are capable of switching industrial components such as solenoids, contactors and starter motors. Reed relays consists of two reeds. When a magnetic force is applied, such as an electromagnet or coil, it sets up a magnetic field in which the end of the reeds assume opposite polarity. When the magnetic field is strong enough, the attracting force of the opposite poles overcomes the stiffness of the reeds and draws them together. When the magnetic

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force is removed, the reeds spring back to their original, open position. These relays work very quickly because of the short distance between the reeds. 7.2.2 SOLID STATE RELAYS Solid state relays consist of an input circuit, a control circuit and an output circuit. The Input Circuit is the portion of a relays frame to which the control component is connected. The input circuit performs the same function as the coil of electromechanical relays. The circuit is activated when a voltage higher than the relays specified Pickup Voltage is applied to the relays input. The input circuit is deactivated when the voltage applied is less than the specified minimum Dropout voltage of the relay. The voltage range of 3 VDC to 32 VDC, commonly used with most solid-state relays, makes it useful for most electronic circuits. The Control Circuit is the part of the relay that determines when the output component is energized or de-energized. The control circuit functions as the coupling between the input and output circuits. In electromechanical relays, the coil accomplishes this function. A relays Output Circuit is the portion of the relay that switches on the load and performs the same function as the mechanical contacts of electromechanical relays. Solid-state relays, however, normally have only one output contact.

Figure 7.3 Solid state relay

7.2.2.1 TYPE OF RELAYS

1. Zero-Switching Relays - relays turns ON the load when the control (minimum operating) voltage is applied and the voltage of the load is close to zero. Zero-Switching relays turn OFF the load when the control voltage is removed and the current in the load is close to zero. Zero-Switching relays are the most widely used.

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2. Instant ON Relays - turns ON the load immediately when the pickup voltage is present. Instant ON Relays allow the load to be turned ON at any point in it's up and down wave.

3. Peak Switching Relays - turns ON the load when the control voltage is present, and the voltage of the load is at its peak. Peak Switching relays turn OFF when the control voltage is removed and the current in the load is close to zero.

4. Analog Switching Relays - has an infinite number of possible output voltages within the relays rated range. Analog switching relays have a built in synchronizing circuit that controls the amount of output voltage as a function of the input voltage. This allows a Ramp-Up function of time to be on the load. Analog Switching relays turn OFF when the control voltage is removed and current in the load is near zero.

7.3 A RELAYS CONTACT LIFE A relays useful life depends upon its contacts. Once contacts burn out, the relays contacts or the entire relay has to be replaced. Mechanical Life is the number of operations (openings and closings) a contact can perform without electrical current. A relays mechanical life is relatively long, offering up to 1,000,000 operations. A relays Electrical life is the number of operations (openings and closings) the contacts can perform with electrical current at a given current rating. A relays Contact electrical life ratings range from 100,000 to 500,000 cycles.

Figure 7.4 contact life

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CHAPTER 8 MISELLANEOUS COMPONENTS

8.1 PUSH BUTTONS Push Button Switches consist of a simple electric switch mechanism which controls some aspect of a machine or a process. Buttons are typically made out of hard material such as plastic or metal. The surface is usually shaped to accommodate the human finger or hand, so the electronic switch can be easily depressed or pushed. Also, most Push Button Switches are also known as biased switches. A biased switch, can be also considered what we call a "momentary switch" where the user will push-for "on" or push-for "off" type. This is also known as a push-to-make (SPST Momentary) or push-to break (SPST Momentary) mechanism. Switches with the "push-to-make" (normally-open or NO) mechanism are a type of push button electrical switch that operates by the switch making contact with the electronic system when the button is pressed and breaks the current process when the button is released. An example of this is a keyboard button. A "push-to-break" (or normally-closed or NC) electronic switch, on the other hand, breaks contact when the button is pressed and makes contact when it is released.

Figure 8.1 Push button

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8.1.1 TYPES OF PUSH BUTTONS There are many different kinds of pushbutton switches and at Future Electronics we stock many of the most common types. We carry some of the top pushbutton switches manufacturers and suppliers including: Altech, C & K, Carling, Cherry Electric, E-Switch, EECO, Grayhill, Marquardt Switches, NKK Switches, Schurter and TE Connectivity Best of all our electronic push button switch offering comes in a range of sizes from miniature to industrial power switches. There are even illuminated pushbutton switches available. Use our parametric filters to refine your electric push button switch search on our website. You can select by number of positions, by circuitry, by actuator style and by termination among others. 8.1.2 USES OF PUSH BUTTONS The "push-button" has been utilized in calculators, push-button telephones, kitchen appliances, and various other mechanical and electronic devices, home and commercial. In industrial and commercial applications, push buttons can be connected together by a mechanical linkage so that the act of pushing one button causes the other button to be released. In this way, a stop button can "force" a start button to be released. This method of linkage is used in simple manual operations in which the machine or process have no electrical circuits for control. Pushbuttons are often color-coded to associate them with their function so that the operator will not push the wrong button in error. Commonly used colors are red for stopping the machine or process and green for starting the machine or process. Red pushbuttons can also have large heads (called mushroom heads) for easy operation and to facilitate the stopping of a machine. These pushbuttons are called emergency stop buttons and are mandated by the electrical code in many jurisdictions for increased safety. This large mushroom shape can also be found in buttons for use with operators who need to wear gloves for their work and could not actuate a regular flush-mounted push button. As an aid for operators and users in industrial or commercial applications, a pilot light is commonly added to draw the attention of the user and to provide feedback if the button is pushed. Typically, this light is included into the center of the pushbutton and a lens replaces the pushbutton hard center disk. The source of the energy to illuminate the light is not directly tied to the contacts on the back of the pushbutton but to the action the pushbutton controls. In this way a start button when pushed will cause the process or machine operation to be started and a secondary contact designed into the operation or process will close to turn on the pilot light and signify the action of pushing the button caused the resultant process or action to start.

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8.2 FREE WHEEL A freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated. The condition of a driven shaft spinning faster than its driveshaft exists in most bicycles when the rider holds his or her feet still, no longer pushing the pedals. In a fixed-gear bicycle, without a freewheel, the rear wheel would drive the pedals around.

Figure 8.2 Free wheel

8.3 WHEEL A wheel is a circular component that is intended to rotate on an axle bearing. The wheel is one of the main components of the wheel and axle which is one of the six simple machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily facilitating movement or transportation while supporting a load, or performing labor in machines. Wheels are also used for other purposes, such as a ship's wheel, steering wheel, potter's wheel and flywheel.

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8.3.1 WHEEL SPECIFICATION Diameter - 7cm; Width - 4cm Shaft Hole - 6mm Easily fits into a 6mm shaft DC gear motor

Figure 8.3 wheel

8.4 CONVEYER BELT Belt conveyor is a machine transporting material in a continuous way by friction drive. It is mainly composed by rack, conveyor belt, belt roll, tensioning device and gearing. It can form a material delivery process between the initial feeding point and the final discharging point of jaw crusher . It can transport not only granular material, but also work piece. Besides the pure material transporting, it can also form a rhythmic flow transport line complying with the requirements of various industrial production processes. The belt conveyor can be used for horizontal transportation or inclined transportation

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in a convenient way, and widely used in modern industrial enterprises, such as: mine tunnel, mine surface transportation system, open-pit and concentrator.

Figure 8.4 Conveyor belt 8.4.1 WORKING PRINCLIPLE Belt conveyor is composed by two endpoint pulleys and a closed conveyor belt. The pulley that drives conveyor belt rotating is called drive pulley or transmission drum; the other one–only used to change conveyor belt movement direction–is called bend pulley. Drive pulley is driven by the motor through reducer, and conveyor belt dragging relies on the friction drag between the drive pulley and the conveyor belt. The drive pulleys are generally installed at the discharge end in order to increase traction and be easy to drag. Material is fed on the feed-side and landed on the rotating conveyor belt, then rely on the conveyor belt friction to be delivered to discharge-end. Feature: The belt conveyor mainly has the following characteristics: the body can flex easily with a belt-warehousing, the tail can elongate or shorten complying with the coal face; directly lay on the roadway floor without setting up foundation; compact structure, light and handy rack and convenient disassembly. When the transmission capacity is big or transport distance is far, we can meet the requirements by equipping with intermediate drives. According to the requirements of transmission process, it can be transported by single transmission and also can be formed a horizontal or inclined transportation-by-multi-unit. The belt conveyor is widely used in metallurgy, coal, transportation, utilities,

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chemical and other departments because of its features of big conveying capacity, simple structure, easy-to- maintenance, low cost and versatility. The belt conveyor is also used in building materials, electricity, light, food, ports, ships. 8.5 DC GEARED MOTOR A gear motor is a specific type of electrical motor that is designed to produce high torque while maintaining a low horsepower, or low speed, motor output. Gear motors can be found in many different applications, and are probably used in many devices in your home. Gear motors are commonly used in devices such as can openers, garage door openers, washing machine time control knobs and even electric alarm clocks. Common commercial applications of a gear motor include hospital beds, commercial jacks, cranes and many other applications that are too many to list.

Figure 8.5 DC Geared motor

8.5.1 WORKING PRINCLIPLE A gear motor can be either an AC (alternating current) or a DC (direct current) electric motor. Most gear motors have an output of between about 1,200 to 3,600 revolutions per minute (RPMs). These types of motors also have two different speed specifications: normal speed and the stall-speed torque specifications.

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Gear motors are primarily used to reduce speed in a series of gears, which in turn creates more torque. This is accomplished by an integrated series of gears or a gear box being attached to the main motor rotor and shaft via a second reduction shaft. The second shaft is then connected to the series of gears or gearbox to create what is known as a series of reduction gears. Generally speaking, the longer the train of reduction gears, the lower the output of the end, or final, gear will be. An excellent example of this principle would be an electric time clock (the type that uses hour, minute and second hands). The synchronous AC motor that is used to power the time clock will usually spin the rotor at around 1500 revolutions per minute. However, a series of reduction gears is used to slow the movement of the hands on the clock. For example, while the rotor spins at about 1500 revolutions per minute, the reduction gears allow the final second hand gear to spin at only one revolution per minute. This is what allows the second-hand to make one complete revolution per minute on the face of the clock.

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CHAPTER 9 SWITCH MODE POWER SUPPLY

The electronic power supply integrated with the switching regulator for converting the electrical power efficiently from one form to another form with desired characteristics is called as Switch-mode power supply. It is used to obtain regulated DC output voltage from unregulated AC or DC input voltage. Similar to other power supplies, switch-mode power supply is a complicated circuit that supplies power from a source to loads. switch-mode power supply is essential for power consuming electrical and electronic appliances and even for building electrical and electronic projects.

Figure 9.1 SMPS

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9.1 WORKING OF SMPS Power supply is an electronic circuit that is used for providing the electrical power to appliances or loads such as computers, machines, and so on. These electrical and electronic loads require various forms of power at different ranges and with different characteristics. So, for this reason the power is converted into the required forms (with desired qualities) by using some power electronic converters or power converters. Electrical and electronic loads work with various forms of power supplies, such as AC power supply, AC- to-DC power supply, High-voltage power supply, Programmable power supply, Uninterruptable power supply and Switch-mode power supply.

9.2 TOPOLOGIES OF SMPS There are different types of topologies for SMPS, among those, a few are as follows: -

DC to DC converter AC to DC converter Fly back converter Forward converter

9.2.1 DC TO DC CONVERTER SMPS In a DC-to-DC converter, primarily a high-voltage DC power is directly obtained from a DC power source. Then, this high-voltage DC power is switched at a very high switching speed usually in the range of 15 KHz to 50 KHz.

And then it is fed to a step-down transformer which is comparable to the weight and size characteristics of a transformer unit of 50Hz. The output of the step-down transformer is further fed into the rectifier. This filtered and rectified output DC power is used as a source for loads, and a sample of this output power is used as a feedback for controlling the output voltage. With this feedback voltage, the ON time of the oscillator is controlled, and a closed-loop regulator is formed.

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Figure 9.2 DC to DC Converter

The output of the switching-power supply is regulated by using PWM (Pulse Width Modulation). As shown in the circuit above, the switch is driven by the PWM oscillator, such that the power fed to the step-down transformer is controlled indirectly, and hence, the output is controlled by the PWM, as this pulse width signal and the output voltage are inversely proportional to each other. If the duty cycle is 50%, then the maximum amount of power is transferred through the step-down transformer, and, if duty cycle decreases, then the amount of power transferred will decrease by decreasing the power dissipation. 9.2.2 AC TO DC CONVERTER SMPS The AC to DC converter SMPS has an AC input. It is converted into DC by rectification process using a rectifier and filter. This unregulated DC voltage is fed to the large-filter capacitor or PFC (Power Factor Correction) circuits for correction of power factor as it is affected. This is because around voltage peaks, the rectifier draws short current pulses having significantly high-frequency energy which affects the power factor to reduce.

Figure 9.3 AC to DC Converter

It is almost similar to the above discussed DC to DC converter, but instead of direct DC power supply, here AC input is used. So, the combination of the rectifier and filter, shown in the block diagram is used for converting the AC into DC and

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switching is done by using a power MOSFET amplifier with which very high gain can be achieved. The MOSFET transistor has low on-resistance and can withstand high currents. The switching frequency is chosen such that it must be kept inaudible to normal human beings (mostly above 20KHz) and switching action is controlled by a feedback utilizing the PWM oscillator. This AC voltage is again fed to the output transformer shown in the figure to step down or step up the voltage levels. Then, the output of this transformer is rectified and smoothed by using the output rectifier and filter. A feedback circuit is used to control the output voltage by comparing it with the reference voltage. 9.2.3 FLY-BACK CONVERTER TYPE SMPS The SMPS circuit with very low output power of less than 100W (watts) is usually of Fly-back converter type SMPS, and it is very simple and low- cost circuit compared to other SMPS circuits. Hence, it is frequently used for low-power applications.

The unregulated input voltage with a constant magnitude is converted into a desired output voltage by fast switching using a MOSFET; the switching frequency is around 100 kHz. The isolation of voltage can be achieved by using a transformer. The switch operation can be controlled by using a PWM control while implementing a practical fly-back converter. Fly-back transformer exhibits different characteristics compared to general transformer. The two windings of the fly-back transformer act as magnetically coupled inductors. The output of this transformer is passed through a diode and a capacitor for rectification and filtering. As shown in the figure, the voltage across this filter capacitor is taken as the output voltage of the SMPS.

FLY-BACK Converter

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9.2.4 FORWARD CONVERTER TYPE SMPS Forward converter type SMPS is almost similar to the Fly-back converter type SMPS, but in the forward converter type, a control is connected for controlling the switch and at the output of the secondary winding of the transformer, and the rectification and filtering circuit is complicated as compared to the fly-back converter.

It can be called as a DC to DC buck converter, along with a transformer used for isolation and scaling. In addition to the diode D1 and capacitor C, a diode D2 and an inductor L are connected at the output end. If switch S gets switched ON, then the input is given to the primary winding of the transformer, and hence, a scaled voltage is generated at the secondary winding of the transformer.

Figure 9.5 FORWARD Converter

Thus, the diode D1 gets forward biased and scaled voltage is passed through the low-pass filter preceding the load. If the switch S is turned off, then the currents through the primary and secondary winding reach to zero, but the current through the inductive filter and load can not be change abruptly, and a path is provided to this current by the freewheeling diode D2. By using the filter inductor, the required voltage across the diode D2 and to maintain the EMF required for maintaining the continuity of the current at inductive filter.

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CHAPTER 10 SOFTWARE & CODING

WPLSoft is a software for PLC (Programmable logic controller). When PLC is in operation, use WPLSoft to monitor the set value or temporarily saved value in timer (T), counter (C), and register (D) and force On/Off of output contacts. PLC is a control system using electronic operations. WPLSoft is a program-editing software made for the Delta DVP-PLC series used under WINDOWS. Except for general program planning and other general functions (e.g. cut, paste, copy, multi-windows, etc.) of WINDOWS, WPLSoft, in addition, has provided various Chinese/English commentary-editing and other special functions (e.g. survey and edit the listed register, the setup, the data readout, the file saving, and monitor and set up diagrams of various contacts, etc.). What follows is the system requirement to comply with the operation environment of WPLSoft:

System requirements for software

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Fig:10.1 Coding

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Fig:10.2 Coding

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Fig:10.3 Coding

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Fig:10.4 Coding

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Fig:10.5 Coding

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CHAPTER 11 CONCLUSION

Thus system designed is very precise and very easy in handling. This system is advantageous for commercial as well as residential purpose. The components used are readily available which makes construction very easy. The structure is compact which allows the system to be installed on any platform. Here, PLC is used in the control of the prototype of the automated parking system. Push buttons, DC motors are used to provide movements to transport the vehicle in the parking system. The main advantages are space optimization, cost effectiveness and security.

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REFERENCES http://www.ijesit.com/Volume%204/Issue%202/IJESIT201502_52.pdfMaizidi

and Maizidi- Embeded system http://www.slideshare.net/jermybsowmya/automatic-car-parking-system-

16284488 http://ijset.com/ijset/publication/v2s9/IJSET_2013_912.pdf https://en.wikipedia.org/wiki/SCADA https://en.wikipedia.org/wiki/Proximity_sensor https://en.wikipedia.org/wiki/Push-button http://en.wikipedia.org/wiki/Programmable_logic_controller R. K. Rajput, Strength Of Meterials, S. Chand http://www.parkingsystemsolutions.com/rotary E. S. Kardoss, K. Baliant, I. Wahl, “Design of a Semi Aautonomous Park

Assist System,” Proceedings of The European Control Conference,2009, pp. 497-516

http://www.delta.com.tw/product/em/em_main.asp https://en.wikipedia.org/wiki/Automated_parking_system https://en.wikipedia.org/wiki/Car_parking_system http://wplsoft.software.informer.com/ https://en.wikipedia.org/wiki/Delta_Electronics